Should I contact the original app developers and propose a deal ? The app is super secured, and I did not find any security breach, I just reverse-engineered it. So I am not sure it will interest them. The app has over 90 million users, and as far as went my research, it seems the API documentation never appeared online.
Should I publish a paid app with additional features not in the original app, or make it free with ads ? Is it legal ? I am in EU.
Should I start a blog, explain how I did, and offer to sell the documentation ? Is it legal ?
Should I sell it on the blackmarket ?
Should I write an article and sell the article to a popular website ? Which one ? Is it legal ?
Should I start a blog, stay vague and grow an audience ? Then how to make profit ?
Overall, what is legal ? Which is the more profitable ? Is there other ways ?